Controlled range proximity fuze

ABSTRACT

An electronic, digital time fuze has a counter which also serves as a serial programmer and which may be remotely preset while in flight to enable a proximity detector circuit at a first predetermined range, and to self detonate the fuze, if not sooner detonated by the proximity detector circuit, at a second predetermined range.

United States Patent Ziemba 1 June 20, 1972 s41 CONTROLLED RANGE PROXIMITY 3,538,506 11/1970 Wiley, Jr. ..102 70.2 R FUZE 3,538,507 11/1970 Wiley, Jr. ..102 70.2 R

[72] Inventor: Richard T. Ziemba, Burlington, Vt. primary Examiner Benjamin Bel-Che [73] Assignee: Genera] E'ecuic Company Assistant Examiner-Thomas H. Webb Attorney-Baum L. Kuch, Harry C. Burgess, Irving M. Freed- [22] Flledi May 11, 19 man, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. 211 App]. NO.2 36,118 Farm" [57] ABSTRACT [52] US. Cl... ..102/70.2P 51 1111. c1 ...F42c 13/00, F42c 11/00, F42 9/00 fuze g ff 2 58 Field of Search ..102/70.2 R, 70.2 P Serves *"i Pmgamme may 6 F e Y preset wh1le 1n fllght to enable a prox1m1ty detector C1rcu1t at a first predetermined range, and to self detonate the fuze, if not [56] References Cited sooner detonated by the proximity detector circuit, at a UNITED STATES PATENTS second predetermined range.

3,027,837 4/1962 Kendall ..l02/70.2 R 5 Claims, 1 Drawing Figure COMMAND REMOTE PULSES \llMhi) REiiglVING ANTENNA I6 14 1 18 2O 22 lo 3 DETECTOR- l 1 T OUTPUT AMPLIFIER CIOUIIVTEIR T T DETONATOR 1 2 62 INHIBI; LATCH 28/ \30 .1 DELAY as DELAY SINGLE SHOT MV (5QMSEC) (IO MSEC) (250/EC) 54 \94 LOCAL f OSCILLATOR 72- INHIBIT LATCH (I00 H!) 84 TRANSMITTING POWER LEVEL OSCILLATOR MONITOR LP PROXIMITY TRANSMITTING 82 ANTENNA 78 CONTROLLED RANGE PROXIMITY FUZE BACKGROUND OF THE INVENTION l. Field of Art This invention relates generally to fuze actuating systems, and especially to systems having an inflight variable range adjustment.

2. Prior Art In my earlier application, Ser. No. 843,478, filed July 22, 1969, there is shown an electronic, digital time fuze, whose time base is introduced over a radar command link at a rate which is inversely proportional to the desired projectile flight time. A target following ranging device, such as a ranging laser, provides target range information to a pulsed radar transmitter. The range signal from the ranging device controls a variable pulse rate control unit which in turn adjusts the transmitter pulse rate to a value which is inversely proportional to the target range. The transmitter is fixed to the weapon system and radiates in the direction of the projectile flight path. Each projectile includes a fuze actuating circuit consisting of an antenna, an r.f. detector, a fixed-set counter and a firing circuit. At launch, the fuze actuating circuit within each projectile becomes activated a short distance after departure from the gun muzzle. As the projectile travels towards its target it receives a series of r.f. pulses at a rate which will just fill the counter when the projectile is at the proper range. The counter within the fuze counts the pulses received during its flight to target. When the final count has been accumulated, the firing circuit detonates the payload. Once the rate at which pulses are to be generated is set, as a function of range, each projectile must travel the same time, and the same range, before it accumulates the same final count. Thus, by adjusting the pulse rate frequency of the transmitter, the gunner adjusts the range at which the payload is detonated.

BRIEF SUMMARY OF THE INVENTION It is an object of this invention to provide an improved system of the type shown in Ser. No. 843,468 which may not only be used as a controlled range detonating fuze, but alternatively, as a true proximity fuze which is enabled at a controlled range and which if not sooner detonated, is self destructed, at a greater controlled range.

A feature of this invention is an electronic, digital time fuze having a counter which also serves as a serial programmer and which may be remotely preset while in flight to enable a proximity detector circuit at a first predetermined range, and to self detonate the fuze, if not sooner detonated by the proximity detector circuit, at a second predetermined range.

BRIEF DESCRIPTION OF THE DRAWING These and other objects, features and advantages of the invention will be apparent from the following specification thereof taken in conjunction with the accompanying drawing in which:

The FIGURE is a block diagram of the electronic circuitry of a controlled range enabled proximity fuze embodying this invention.

THE PREFERRED EMBODIMENT A fuze embodying this invention is designed around a counter having a plurality of outputs at respective predetermined counts, and thereby serving as a serial programmer. The counter may be mechanized as a series of bistable flip-flops with appropriate decoding gates. To permit the counter to be remotely pulsed by a radar command link after the round has been launched from the gun, the fuze is provided with antenna receiving slots 12 which are coupled to the signal input terminal 14 of a detector-amplifier circuit 16 having a signal output terminal 18. The terminal 18 is coupled to a first signal input terminal 20 of an OR gate 22 having a second signal input terminal 24 and an output signal terminal 26. The

terminal 26 is coupled to the input terminal 27 of the counter 10 which has a first, intermediate count, output terminal 28, a second, intermediate count, output temrinal 30, and a third, full count, output terminal 32. The terminal 32 is coupled to a first signal input terminal 34 of an OR gate 36 which has a second signal input terminal 38 and a signal output terminal 40. The temiinal 40 is coupled to a signal input terminal 42 of a firing or output-detonator circuit 44.

A local oscillator 50 has a pulse output terminal 52 coupled to the input terminal 54 of a first pulse delay network 56 having an output terminal 58. The terminal 58 is coupled to the inhibit terminal 60 of a first inhibit latching circuit 62 which is coupled to the detector-amplifier 16. The terminal 52 is also coupled to the second signal input terminal 24 of the OR gate 22.

The first, intermediate count, output terminal 28 of the counter 10 is coupled to the input terminal 64 of a second pulse delay network 66 having an output terminal 68 which is coupled to the enable input terminal 70 of a second inhibit latching circuit 72 having an inhibit input terminal 74. The circuit 72 is coupled to a transmitting oscillator 76 having a pulse output terminal 78 coupled to a transmitting antenna 80, which may be of the helical type. The oscillator 76 also has a power level monitoring terminal 82 which is coupled to an input terminal 84 of a power level monitoring circuit 86 having an output terminal 88 providing an output signal in response to a low power level, e.g. a loaded transmitter. The terminal 88 is coupled to the second input terminal 38 of the OR gate 36.

The second, intermediate count, output terminal 30 is coupled to the input terminal 90 of a single shot multivibrator 92 having an output terminal 94 coupled to the inhibit input terminal 74 of the inhibit latch circuit 72.

A power source, not shown, is coupled to the various active circuits as required. This power source may be provided by a high rate of rise thermal battery; or by a piezoelectric source coupled to the detector-amplifier 16, local oscillator 52 and counter 10 for instantaneously available low power, and by a thermal battery coupled to the transmitting oscillator 76 and firing circuit 44 for delayed high power. The counter may be of the type that assumes the reset state upon the application of power thereto. Alternatively, a reset circuit, such as shown by Robert A. Leightner in Ser. No. 843,625, filed July 22, 1969, and assigned to a common assignee, may be coupled to the counter to coerce the counter to its reset state on energization.

Immediately after the projectile is launched from the weapon, e.g. within 50 milliseconds, a burst of r.f. pulses is transmitted to the fuze in the traveling projectile from a low power, high frequency, e.g. l Mhz., transmitter adjacent the weapon. These pulses are re received by the fuze via a plurality of slot antennas 12 disposed in the ogive of the projectile fuze. These pulses are rectified in the detector/amplifier circuit 16 and fed via the OR gate 22 to the input of the binary counter 10. The binary counter 10 has a second input from the local oscillator 50 within the fuze. This oscillator may operate at H,, and is enabled at the launching of the projectile, and continues to function throughout the flight of the projectile. The local oscillator is also coupled to the detector inhibit latching circuit 62, via the 50 millisecond delay unit 56. At approximately 100 milliseconds after projectile launch, the first pulse generated by the local oscillator arrives at the detector inhibit latching circuit to effect the disabling of the detector. The receiving circuit is thus disabled for the remainder of the flight of the projectile, precluding electronic counter-measures from effecting the fuze. The counter is a multi-stage, serial, binary logic device, with appropriate decoding gates, whose final output initiates the detonator circuit 44 to detonate the projectile warhead.

The fuze is designed to function in two alternative modes, i.e., either as an electronic time fuze, or as a proximity fuze. The mode may be selected remotely.

To function the fuze in the proximity mode, r.f. pulses are initially transmitted in a burst to the fuze immediately after launch, as described previously. However, the quantity of pulses so transmitted is only sufficient to provide an output pulse T at the first output terminal 28 at approximately 1 second before ground impact, when taken in conjunction with the pulses provided by the local oscillator 50 at a fixed rate, e.g. 100 pps, during the flight. The T pulse is delayed a few milliseconds, e. g. milliseconds, after which it enables the proximity transmitting oscillator 76 which feeds the transmitting antenna 50. An output pulse T at the second output terminal 30, which may be programmed to occur approximately 1 second after T,, will trigger the single shot multibrater 92 to latch the proximity oscillator into a permanently disabled condition. The presence of a target, ground or aircraft, in the near field of the antenna, will load the transmitting oscillator 76, reducing its output power level, which will be detected by the monitor 86 which will trigger the fuze detonate circuit 44. Meanwhile the local oscillator continues to advance the counter, and in the event the monitor has not already triggered the detonator, the provision of an output pulse T at the final output tenninal 32 will trigger the detonate circuit 44.

To function the fuze in the time mode, r.f. pulses are initially transmitted in a burst to the fuze immediately after launch. Sufficient r.f. pulses at l Mhz. are provided to fill the counter beyond the output terminals 28 and 30. Since the T pulse which is one microsecond wide, is delayed 10 milliseconds en route to the proximity transmitting oscillator 76, the T pulse will arrive to trigger the single shot multiplier to generate a 250 microsecond wide pulse to latch the oscillator off before the T pulse arrives to start it, and which wide pulse extends after the termination of the delayed T pulse, thereby precluding the transmitting oscillator from generating any pulses. The local oscillator 50 starts up and pulses the counter until it is filled to provide a T pulse at the final output terminal to trigger the detonate circuit 44.

While there has been shown and described a preferred embodiment of this invention, it will be appreciated that the invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying idea or principles of this invention within the scope ofthe appended claims.

What is claimed is:

l. A fuze for a projectile, comprising:

a counter including an input terminal,

first output terminal for providing a first output signal at a first count, and

a final output terminal for providing a final output signal at a final count greater than said first count;

a circuit for receiving pulses from an outside source, including a receiving antenna, an r.f. detector having an input terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto;

a local oscillator circuit having an output terminal coupled to said receiving circuit for providing a pulse thereto precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal and also coupled to said counter input terminal for providing pulses thereto;

a proximity circuit, including:

a transmitting antenna,

a transmitting oscillator having an output terminal cou pled to said transmitting antenna for providing energy thereto, and an input terminal coupled to said counter first terminal for enabling the provision of energy by said transmitting oscillator to said transmitting antenna at and subsequent to said first count, and

means for detecting the presence of a target in the near field of said transmitting antenna when said antenna is energized by said transmitting oscillator and having an output terminal for providing a signal in response to such detection; and an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count, and

a second input terminal coupled to said proximity detecting means output terminal for providing an output function in response to the detection of the presence of a target in the near field of said transmitting antenna.

2. A fuze according to claim 1, wherein said counter further includes a second output terminal for providing a second output signal at a second count, which second count is greater than said first count and smaller than said final count; and

said proximity circuit further includes latchable means, for inhibiting the functioning of said proximity circuit, having an input terminal coupled to said counter second output terminal, thereby precluding the provision of a signal in response to the presence of a target in the near field of said transmitting antenna at and subsequent to said second count.

3. A dual alternative function fuze, for proximity or controlled range detonation, comprising:

a counter including an input terminal,

a first output terminal for providing a first output signal at a first count,

a second output terminal for providing a second output signal at a second count, which second count is greater than said first count, and

a final output terminal for providing a final output signal at a final count, which final count is greater than said second count;

a circuit for receiving pulses from an outside source, including a receiving antenna an r.f. detector having an input terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto;

first latchable means, normally disabled, for inhibiting the functioning of said receiving circuit, having an input terminal,

a local oscillator circuit having an output terminal coupled to said first latchable means for providing a pulse thereto for precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal, and also coupled to said counter input terminal for providing pulses thereto;

a proximity circuit, including a transmitting antenna,

a delay means,

a transmitting oscillator having an output terminal coupled to said transmitting antenna for providing energy thereto, and an input terminal coupled via said delay means to said counter first terminal for enabling the provision of energy by said transmitting oscillator to said transmitting antenna at a fixed time subsequent to said first count,

means for detecting the presence of a target in the near field of said transmitting antenna when said antenna is energized by said transmitting oscillator, and having an output terminal for providing a signal in response to such detection, and

latchable means for inhibiting the functioning of said proximity circuit, having an input terminal coupled to said counter second output terminal for precluding the provision of a signal in response to the presence of a target in the near field of said transmitting antenna at and subsequent to said second count;

an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count, and a second input terminal coupled to said proximity detecting means output terminal for providing an output function in response to the detection of the presence of a target in the near field of said transmitting antenna;

whereby if said pulses provided by said r.f. detector run the count in said counter up to or beyond said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, said fuze will omit any proximity function, and output function will be provided by said final count signal; but, if said pulses provided by said r.f. detector run the count not up to said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, then said fuze will provide a proximity function, and output function will be provided by the first to occur of target detection and signal and final count signal.

4. A weapons system comprising:

an r.f. pulse transmitter having a transmitting antenna; and

a projectile having a dual, alternative function fuze, for

proximity or controlled range detonation, comprising:

a counter including an input terminal,

a first output terminal for providing a first output signal at a first count,

a second output terminal for providing a second output signal at a second count, which second count is greater than said first count, and

a final output terminal for providing a final output signal at a final count, which final count is greater than said second count;

a circuit for receiving pulses from an outside source, in-

cluding a receiving antenna,

an r.f. detector having an output terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto;

first latchable means, normally disabled for inhibiting the functioning of said receiving circuit, having an input terminal,

a local oscillator circuit having an output terminal coupled to said first latchable means for providing a pulse thereto for precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal, and also coupled to said counter input terminal for providing pulses thereto;

a proximity circuit, including a transmitting antenna,

a delay means,

a transmitting oscillator having an output terminal coupled to said transmitting antenna for providing energy thereto, and an input terminal coupled via said delay means to said counter first terminal for enabling the provision of energy by said transmitting oscillator to said transmitter antenna at a fixed time subsequent to said first count,

means for detecting the presence of a target in the near field of said transmitting antenna when said antenna is energized by said transmitting oscillator, and having an output terminal for providing a signal in response to such detection, and

latchable means for inhibiting the functioning of said proximity circuit, having an input terminal coupled to said counter second output terminal for precluding the provision of a signal in response to the presence of a target in the near field of said transmitting antenna at and subsequent to said second count;

an output function circuit, includin a first input terminal coupled to said counter final output terminal for providing an output function at the final count, and

a second input terminal coupled to said proximity detecting means output terminal for providing an output function in response to the detection of the presence of a target in the near field of said transmitting antenna;

whereby if said pulses provided by said r.f. detector run the count in said counter up to or beyond said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, said fuze will omit any proximity function, and output function will be provided by said final count signal; but, if said pulses provided by said r.f. detector run the count not up to said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, then said fuze will provide a proximity function, and output function will be provided by the first to occur of target detection and signal and final count signal.

5. A fuze for a projectile, comprising:

a counter including an input terminal, first output terminal for providing a first output signal at a first count, and

a final output terminal for providing a final output signal at a final count greater than said first count;

a circuit for receiving pulses from an outside source, including a receiving antenna,

a r.f. detector having an input terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto;

a local oscillator circuit having an output terminal coupled to said receiving circuit for providing a pulse thereto precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal and also coupled to said counter input terminal for providing pulses thereto;

an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count. 

1. A fuze for a projectile, comprising: a counter including an input terminal, first output terminal for providing a first output signal at a first count, and a final output terminal for providing a final output signal at a final counT greater than said first count; a circuit for receiving pulses from an outside source, including a receiving antenna, an r.f. detector having an input terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto; a local oscillator circuit having an output terminal coupled to said receiving circuit for providing a pulse thereto precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal and also coupled to said counter input terminal for providing pulses thereto; a proximity circuit, including: a transmitting antenna, a transmitting oscillator having an output terminal coupled to said transmitting antenna for providing energy thereto, and an input terminal coupled to said counter first terminal for enabling the provision of energy by said transmitting oscillator to said transmitting antenna at and subsequent to said first count, and means for detecting the presence of a target in the near field of said transmitting antenna when said antenna is energized by said transmitting oscillator and having an output terminal for providing a signal in response to such detection; and an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count, and a second input terminal coupled to said proximity detecting means output terminal for providing an output function in response to the detection of the presence of a target in the near field of said transmitting antenna.
 2. A fuze according to claim 1, wherein said counter further includes a second output terminal for providing a second output signal at a second count, which second count is greater than said first count and smaller than said final count; and said proximity circuit further includes latchable means, for inhibiting the functioning of said proximity circuit, having an input terminal coupled to said counter second output terminal, thereby precluding the provision of a signal in response to the presence of a target in the near field of said transmitting antenna at and subsequent to said second count.
 3. A dual alternative function fuze, for proximity or controlled range detonation, comprising: a counter including an input terminal, a first output terminal for providing a first output signal at a first count, a second output terminal for providing a second output signal at a second count, which second count is greater than said first count, and a final output terminal for providing a final output signal at a final count, which final count is greater than said second count; a circuit for receiving pulses from an outside source, including a receiving antenna an r.f. detector having an input terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto; first latchable means, normally disabled, for inhibiting the functioning of said receiving circuit, having an input terminal, a local oscillator circuit having an output terminal coupled to said first latchable means for providing a pulse thereto for precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal, and also coupled to said counter input terminal for providing pulses thereto; a proximity circuit, including a transmitting antenna, a delay means, a transmitting oscillator having an output terminal coupled to said transmitting antenna for providing energy thereto, and an input terminal coupled via said delay means to said counter first terminal for enabling the provision of energy by said transmitting oscillator to said transmitting antenna at a fixed time subsequent to said first count, means for detecting the presence of a target in the near field of said transmitting antenna when said antenna is eNergized by said transmitting oscillator, and having an output terminal for providing a signal in response to such detection, and latchable means for inhibiting the functioning of said proximity circuit, having an input terminal coupled to said counter second output terminal for precluding the provision of a signal in response to the presence of a target in the near field of said transmitting antenna at and subsequent to said second count; an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count, and a second input terminal coupled to said proximity detecting means output terminal for providing an output function in response to the detection of the presence of a target in the near field of said transmitting antenna; whereby if said pulses provided by said r.f. detector run the count in said counter up to or beyond said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, said fuze will omit any proximity function, and output function will be provided by said final count signal; but, if said pulses provided by said r.f. detector run the count not up to said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, then said fuze will provide a proximity function, and output function will be provided by the first to occur of target detection and signal and final count signal.
 4. A weapons system comprising: an r.f. pulse transmitter having a transmitting antenna; and a projectile having a dual, alternative function fuze, for proximity or controlled range detonation, comprising: a counter including an input terminal, a first output terminal for providing a first output signal at a first count, a second output terminal for providing a second output signal at a second count, which second count is greater than said first count, and a final output terminal for providing a final output signal at a final count, which final count is greater than said second count; a circuit for receiving pulses from an outside source, including a receiving antenna, an r.f. detector having an output terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto; first latchable means, normally disabled for inhibiting the functioning of said receiving circuit, having an input terminal, a local oscillator circuit having an output terminal coupled to said first latchable means for providing a pulse thereto for precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal, and also coupled to said counter input terminal for providing pulses thereto; a proximity circuit, including a transmitting antenna, a delay means, a transmitting oscillator having an output terminal coupled to said transmitting antenna for providing energy thereto, and an input terminal coupled via said delay means to said counter first terminal for enabling the provision of energy by said transmitting oscillator to said transmitter antenna at a fixed time subsequent to said first count, means for detecting the presence of a target in the near field of said transmitting antenna when said antenna is energized by said transmitting oscillator, and having an output terminal for providing a signal in response to such detection, and latchable means for inhibiting the functioning of said proximity circuit, having an input terminal coupled to said counter second output terminal for precluding the provision of a signal in response to the presence of a target in the near field of said transmitting antenna at and subsequent to said second count; an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count, and a second input terminal coupled to said proximity detecting means output terminal for providing an output function in response to the detection of the presence of a target in the near field of said transmitting antenna; whereby if said pulses provided by said r.f. detector run the count in said counter up to or beyond said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, said fuze will omit any proximity function, and output function will be provided by said final count signal; but, if said pulses provided by said r.f. detector run the count not up to said second count before said first count signal, as delayed said fixed time, enables said transmitting oscillator, then said fuze will provide a proximity function, and output function will be provided by the first to occur of target detection and signal and final count signal.
 5. A fuze for a projectile, comprising: a counter including an input terminal, first output terminal for providing a first output signal at a first count, and a final output terminal for providing a final output signal at a final count greater than said first count; a circuit for receiving pulses from an outside source, including a receiving antenna, a r.f. detector having an input terminal coupled to said receiving antenna and an output terminal coupled to said counter input terminal for providing pulses thereto; a local oscillator circuit having an output terminal coupled to said receiving circuit for providing a pulse thereto precluding the subsequent provision of pulses from said receiving circuit to said counter input terminal and also coupled to said counter input terminal for providing pulses thereto; an output function circuit, including a first input terminal coupled to said counter final output terminal for providing an output function at the final count. 